Freezing machine



y 6, N. J. SCHAAL FREEZING MACHINE Filed s pt. 19, 1939 3 Sheets-Sheet 1m mg ON Q M 6, 1947- N. SCHAAL 2,419,954

FREEZING MACHINE Filed Sept. 19, 1939 s Sheets-Shet 2 INVENTOR.

y 1947. N. J. SCHAAL FREEZING MACHINE 7 Filed Sept. 19, 1939 3Sheets-Sheet 5 Patented May 6, 1947 uNi'rEp STATES PATENT or iesFREEZING MACHlNE Norbert J. Schaal, Riverton Heights, Wash.

Application September 19, 1939, Serial No. 295,614

Claims.

My invention relates to improvements in freezing machine for makingcrystalline laminae of frozen liquid, for use in the icing of foodproducts, the cooling of liquids, and other purposes.

Referring to the accompanying drawings, Figure 1 is a view of a portionof one of the crystalline laminae made on my machine. Figure 2 is alongitudinal cross-section view of my machine for the production of saidlaminae, Figure 3 is a transverse section of the same machine. Figure 4is a view of a part of the machine in the area surrounding one of theadjustable bearings. Figure 5 is a cross-section of a portion of thefrozen lamina after it has been stripped from the drum and beforeremoving the embedded wires. Figure 6 is a greatly enlarged section of aportion of the roll and a lamina and-wire at the time when the wireleaves the lamina. Fig. 7 is a systematic diagram showing safety stopsand means for controlling the temperature and thickness of the icelayer.

When food products have been packed in crystalline fragments made byfreezing water or other liquid, or when such crystalline material hasbeen stored in bins or piles and subjected to the action of warm air, ithas been found that the crystalline material lasted longer if it was ina form having relativelylow thermal conductivity.

The thermal conductivity of a, mass of the crystalline material islowest when the percentage of voids is high, when the heat must passthrough a maximum number and area of solid-air interfaces per inch oftravel, and when the contact area between surfaces of adjacent fragmentsis a minimum.

Heretofore, laminae made for the above purposes have been in the form ofalmost flat flakes of very slight curvature. Such flakes possessrelatively little strength and are therefore I easily pressed into goodcontact with one another, thus reducing the percentage of voids,reducing the number and area of solid-air interfaces through which theheat must pass, and increasing the contact area between surfaces ofadjacent fragments.

Lamina made on the machine of the present invention is of such form thatit cannot easily be pressed into intimate contact, over any relativelylarge portion of its surface, with adjacent laminae. Therefore, even fora given thickness of laminae, a mass of these new laminae has lowerthermal conductivity than a mass of the previous type. However, due toits greater strength and frozen. The matrix is kept at a temperature be-7 more effective use of material in resisting distortion, this new formof lamina may be produced than was found most effective inthe formertype.

The use of this smaller thickness naturally results in a still furtherdecrease in the thermal conductivity of a mass of these laminae. I

A very much enlarged view of a portion of a lamina made on the presentmachine is shown in Figure 1. Protuberances in the form of ridges on thetop and bottom surfaces of the lamina act as fenders to prevent theclose contact of more than a minimum proportion of the area of anadjacent lamina, thus ensuring a large percentage of voids. .Also, theridges act as reinforcements, tending to resist breakage of the lamina.

Another advantage of the lamina is the fact that, due to the pluralityof ridges and depressions, the total surface area is relatively large,thus increasing the speed with which heat is absorbed from a liquid intowhich the lamina is immersed for the purpose of coolin such liquid.

In the production of the above described laminae, I place narrow wiresin contact with a freezing matrix of high thermal conductivity, highdensity and high specific heat, having a surface layer with very littleaffinity for the liquid to be low the freezing point of the liquid to befrozen to make the laminae. Liquid is then applied to the matrix andwires are allowed to freeze, thus forming a reinforced lamina of brittlefrozen material, strongly reinforced by the wires. The wires are thenused to strip this reinforced lamina from the matrix.

It has been found that a similar layer of frozen liquid, namely waterice, formed without the reinforcements, resists removal by chipping orscraping, due to the fact that the edges of the lamina often break offbefore sufiicient force can be applied to strip off the main body of thelamina.

After the reinforced lamina has been stripped from the surface of thematrix, the wires must be removed from the lamina. This may be done bystretching the wires to a rigid condition and then applying force to thelamina in such amount and direction as to sever the bond between thewires and the surface of the lamina.

My experiments prove that for best results the wires should becontinuous in their contact over the entire portion of their length thathappens to be in order that the neutral axis of the reinforced lamina,considered as a beam, may be close to the surface on the side toward thematrix, so that practically no stretching of any part of the frozenliquid, with its low tensile strength, may occur during the flexurewhich is necessary in order to remove the lamina from the surface. In myexperiments with wire mesh in place of single parallel wires, I foundthat due to the greater thickness of the mesh, caused by the necessarycrossing of the wires, for a given gauge of wire, the neutral surface ofthe reinforced lamina was at a greater distance from the face of-thelamina toward the matrix. Consequently, the brittle material of thelamina was subjected to tension at the face toward the matrix, at thetime of stripping, resulting in an inferior product.

Since the crystalline lamina is to be flexed in only one direction, itis necessary to reinforce it in only one direction, and wires tending toreinforce it in any other direction would be superfluous and in the way.I therefore find it best to use parallel and mutually independent wires.

I prefer to form such laminae by means of mechanism illustrated in theaccompanying drawings.

Drum I is designed to be rotated about aline through centers of bearings2 and 3. Shaft 4 carries drive sprocket 5. Shaft 6 is h'ollow to allowof the pumping of refrigerating liquid to and from the interior of drumI. Cooling fluid enters fitting I and is distributed to the interior ofdrum I by pipe 8. The cooling fluid leaves drum I by means of annularspace between 6 and roll I8 in the manner of a multiple rope drive.

Water passes into the apparatus through magnetic valve 23 and floatvalve 24. The water is compelled by baflle 25 to pass by therefrigerating coils I6 before coming in contact with the drum I andbelts l'I.

The rotation of drum I, clockwise in Figure 3, causes successiveportions of the wires I1 to be pressed into intimate contact with thesurface of the drum I.

The more or less cylindrical shell of the refrigerated drum I may bemade from hard copper, which has the capacity to absorb a great deal ofheat for a given temperature rise, and

8, and is kept from leaking out by means of pack- Drum I is insulated atthe ends by sealed in-' sulation discs, I3, I3, held in place by metaldiscs I4, I4.

Drum I dips into water in insulated tank I5, which is provided withcooling coils I6 for precooling of the water.

The drum I is grooved on its outer surface to form a suitable matrix forthe ice which is to be formed and to guide the endless wires I'I. Asillustrated in Fig. 1, one side of the ice particle conforms to theirregular, grooved surface of the drum against which it was frozen orcast. If the thickness of the lamina is very small as compared to thedimensions of the grooves, then the opposite surface of the lamina alsoconforms quite closely to the form of the drum surface.

metal mandrel I9 whose ends terminate in journals 20, mounted inadjustable bearings 2i, con trolled by set screws 22.

The endless wires are mounted on drum I and Fig. 1 reprehas a very highthermal conductivity. The outer surface of the drum may be coated withchromium, whose exposed surface, in contact with the atmosphere, becomescoated with a material not easily wet by water.

As the drum turns, the ice lamina 26, together with the embedded wiresI1, is carried up and out of the water and exposed to the cold air ofthe refrigerated room in which this apparatus is to be used. Heatcontinues to be absorbed from the water-ice 26 and it arrives at the topof the drum I at a temperature considerably below its freezing point.

It will be noted that the layer of ice, in combination with the embeddedwires, forms a reinforced beam. That portion which is next to thesurface of the drum I is, as a result of the reinforcing wires I1, verystrong in tension. Without the wires, the ice would naturally be veryweak in tension. The remaining portion of the crosssection of thisreinforced beam is strong in compression. It will be seen that theconditions are ideal for the resisting of force tending to bend thisreinforced beam away from the drum I. Consequently, the portion of thisreinforced beam between the points of tangency 21 and 28 acts, as alever in stripping itself loose from drum I at point of tangency 21.

The cross-section of the ice and wires II, at a point intermediatebetween 21 and 28, is shown in Figure 5. The lower surface of thissection, naturally has the form of the grooved surface of drum I.

The surface of roll I8 is also grooved in a similar manner, except thatthe central portionof each groove is made slightly deeper and thesurface between the grooves is releaved, eliminating the cross groovesentirely, as shown in very much enlarged section in Figure 6.

The wires I! are maintained at sufficient tension to ensure that theyare substantially straight at all points between 21 and their point oftangency 28 on roll I8. The belts therefore continue in a straight linetoward their seats in the bottom of grooves in roll I8, while the icelamina is gently forced upward by the remaining portions of the sides ofthe grooves on roll- I8, thus freeing the belts from the under surfaceof the ice lamina 29] and allowing this lamina to be discharged over thetop of roll I8.

Roll surface I8 is made fromelastic material to allow for individualdifferences in the lengths of the endless wires I1 and to aid in freeingthe surface of roll I8 of small pieces of ice which break loose from theunder side of the lamina 29, next to the wires I1, as shown in Figure 6.Also, said elastic material is used in order that the wires Il may sinkinto the surface of roll I8 an amount depending upon their tension,making it possible, by changing the tension of the wires, to regulatethe pressure exerted in the removal of the ice lamina from the wiresI'I.

Angle iron scraper 30 is designed to prevent small pieces of ice fromdropping down and lodging between the wires I1 and the face of the drumI, thus straining wires I1. The scraper 30 is adjustably mounted on arms3| and pivots about axis of shaft 32. This pivoting is resisted byspring 33, and is provided to prevent breakage of a wire I! if aprojecting joint thereof becomes jammed against scraper 30. Screw 34 isused in the adjusting of the normal position of scraper 30.

Power for'rotating drum I is supplied from mains 35, 35, 35, throughmagnetic switch 36 to motor 31. Magnetic switch 35 is controlled bymeans of push-button switch 38 and contact lever 39. Motor 3'! drivessprocket 5 through variable speed transmission 45, worm reducer 4| andchain 42.

At all times it is desirable to produce laminae of uniform thickness.Accordingly, gauging finger 43 is pressed against the surface of the icethrough the action of the spring 44. Excessive thickness of the ice 26causes the contact lever 45 to touch contact 46. Lever 44 and contacts46 and 41 are connected to reversing magnetic switch 48, which controlsthe direction of rotation of motor 49, which operates the control screw50 of the variable speed transmission 40 through gears-5| and 52. Therelationship of contacts 46 and 41, switch 48 and motor 49, along withmechanical relationships in the speed changer 40 are srarranged that areduction in the thickness of vne ice, beyond a certain point, causesthe drum I to decrease its speed, while if the ice is too thick, thespeed of the drum I will be increased.

Thermostat I2 is electrically connected to the magnetic intake valve 23.This valve is so constructed and adjusted that liquid is allowed to passonly when current flows through its windings. the current to flow tomagnetic valve 23 whenever the cooling fluid passing through saidthermostat is cold enough to indicate that suificient cooling of drum Iis taking place to warrant the application of water to its surface.

If at any time, for any cause, the rotation of the drum I is stopped, orthe action of the refrigerating system stops, it becomes necessary todrain the tank I5 and. prevent the entry of further'water, so as toprevent the formation of an excessive layer of ice in the tank I 5.Magnetic valve 53 is constructed and adjusted so as to allow liquid toflow only when there is no current supplied to its windings. Whenshutting down the machine, the opening of magnetic switch 36 shuts offthe supply of current to magnetic valve 53 and magnetic intake valve 23,draining tank I5 and preventing further intake of water through magneticintake valve 23.

Gear pump 54 is driven by worm reducer 4I. As a result of the action ofpump 54, pressure is built up in tank 55, making contact in pressurestat56, thus not interfering with the action of magnetic valves 23 and 53.However, if worm drive M, and consequently drum I, stops, the pressurein 55 is soon lost through valve 51 and contact is broken inpressurestat 55, thus preventing the flow of current to magnetic valves23 and 53 and so emptying tank l5 and preventing further water fromentering until repairs or corrections are made.

The pressurestat 58 is connected to the suction line of therefrigerating compressor which sup- During operation the thermostat I2allows ice will stick to the tops of the ridges on drum I and will becarried around to contact lever 39', breaking the contact and soshutting off the current supply through the action of magnetic switch36.

Pipe 59 is used in supplying a small quantity of low freezing point oilto the surface of drum I. This oil has a greater wetting tendencytowardchromium than water has, and will displace water on the surface of thatmetal.

I claim:

1. A machine for the freezing of ice comprising a rigid rotatablerefrigeratable drum adapted to contain a refrigerating medium, said drumformed with encircling grooves in spaced relationship therealong, wiresdisposed about and in contact with only a portion of the drum withinsaid grooves, means for applying liquid to the surface of thedrum forfreezin over said wires, and means for rotating the drum whereby thewires will efiect the separation of formed ice from the drum surface.

2. A machine for the production of crystalline laminae of frozen liquidcomprising a rigid rotatable refrigeratable drum adapted to contain arefrigerating medium, said drum formed with circumferential grooves inspaced relationship therealong, a rotatably mounted, roll separate fromthe drum, a plurality of wire belts applied about the roll and drumwithin the grooves of the latter, means for applying a liquid to aportion of the periphery of said drum as it rotates for freezing thereonover said belts, and means for rotating the drum.

3. A machine for the production of crystalline laminae of frozen liquidcomprising a rigid rotatable refrigeratable drum adapted to contain arefrigerating medium, a plurality of separate unconnected parallelendless single wire belts drawn taut and operating about a portion ofthe periphery of said drum, means for applying liquid to a portion ofthe periphery of said drum for freezing thereon over said wires, meansfor rotating the drum for the progressive freezing of ice about itssurface and for the separation of the ice from the surface by the wirebelts, and means for the separation of the ice from said wires.

4. A machine for the production of frozen liquid, comprising: a rigidrotatable refrigeratable drum adapted to contain a refrigerant, a rollspaced from and parallel to said drum, placed about said drum and roll aplurality of spaced apart separate unconnected parallel endless singlewire belts, means for refrigerating said drum, means for rotating saiddrum, and means for supplying a liquid to the surface of said drum forfreezing thereon and stripping therefrom by said belts.

5. A machine for the production of frozen liquid, comprising: a rigidrotatable refrigeratable drum adapted to contain a refrigerant,'-a rollspaced from and parallel to said drum, wire placed about said drum androll in a plurality of runs to form a belt extending around but notcontacting the whole of the circumference of said 7- drum, said wirebeing not cross connected. means for refrigerating said drum, means forrotating said drum, and means for supplying a liquid to the surface ofsaid drum for freezing thereon and stripping therefrom by said belts.

NORBERT JAMES SCHAAL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,005,736 Field June 25, 19352,025,711 Bemis Dec. 31, 1935 2,149,912 Fuss Mar. 7, 1939 607,764 RankinJuly 19, 1898 Number Number Name Dlte Kallander July 28, 1931 BarrettFeb. 25, 1936 Short Sept. 15, 1936 'I'hllenius Mar. 14, 1939 Swab Mar.28, 1940 Bennett Jan. I, 1930 Hathorne Oct, 31, 1933 Field June 25, 1935Anderson Nov. 1, 1938 Field June 10, 1941 Field Apr. 17, 1923 FOREIGNPATENTS Country Date Swiss Aug. 1, 1934

